toussaint



2 Sheets-Sheet 1.

(N0 Model.)

B. TOUSSAINT.

FIELD GLASS.

Patented Oct. 13, 1896.

(No Model.) 2 Sheets-Sheet 2.

E. TOUSSAINT. FIELD GLASS.

No. 569,628. Patented Oct, 13, 1896.

I UNITED STATES PATENT OEEIcE.

EMILE TOUSSAIN", OF BERLIN, GERMANY.

FIELD-GLASS.

SPECIFICATION forming part of Letters Patent No. 569,528, dated October13, 1896.

Application filed June 5, 1896. Serial No. 594,433. (N0 model-l T0 6twhom it may concern:

Be it known that I, EMILE TOUssAINT, a subject of the King of Prussia,Emperor of Germany, and a resident of Berlin, Germany, have inventedcertain new and useful Improvements in Field-Glasses, of which thefollowing is a specification.

This invention has for its object an ar rangement for suddenlyincreasing the degree of magnifying power without necessitating theglass being removed from the eyes in such field-glasses as are moreparticularly used for military observations, as well as by tourists andsportsmen. The arrangement consists in a convex glass being insertedordinarily in front of each of the two oculars of the fieldglass, sothat the magnifying effect produced by the oculars is diminished and bya mechanism being arranged which, by means of one and the same grip ofthe hand, moves aside the convex glasses placed in front of the coularsand simultaneously pushes forward the objectives to an extent whichequals the difference of the focal distance of the objective alone andthe focal distance of the combination of the objective and the convexglass inserted in front of its respective ocular.

In the accompanying drawings, Figure 1 shows an elevation of thefield-glass when shut up, one of the oculars being shown in section withthe convex glass inserted in front of it. Fig. 2 is a horizontal sectionon the line 00 w of Fig. 1. Fig. 3 shows one-half of the field-glasswith the adjusting device when the convex glass is moved aside and theobjectives pushed forward. Separate important parts are shown insection. Fig. 4 is a horizontal section of Fig. 3. Fig. 5 is a sectionof the whole adjusting mechanism. Figs. 6 and 7 are details.

a are the oculars; 0, the objectives.

1) are the convex glasses, which are moved in and out.

The screw of the set-screw I), connected with the framework or settingof the eyeglasses a, is mounted. on a hexagonal sheath or holder 0,Figs. 3, 5, and 6, the innerhollow space of which has a circularsection. In

this hollow space a round spindle cl, Figs. 5 and 6, is mounted, whichis connected with the sheath 0 by means of a pin 6 in such a way that itis displaced longitudinally, to-

gether with the latter, while short diametrical slots f, Figs. 2 and 41,in the sheath 0 allow a small independent rotation of the spindle cl.The latter is slotted from its lower end to a length corresponding tothe maximum displacement of the ocular a, and through this slot g, Figs.5 and 6, a pin 7?. projects, which pin, lying transversely, is attachedto a tube in, revolubly mounted in the bridge i This tube carries a knobI, Fig. 7. If the tube 7t be turned by means of this knob I, it carrieswith it, by means of the pin, the spindle (Z and also the pin 6,attached to the latter. The two ends of this pin engage in the socket mof a two-armed lover a 01 Fig. 2, revoluble on the upper rounded end ofthe hexagonal sheath or holder 0, mounted on the bridge 2", and causethis lever n n to swing in one direction or the other, according to thedirection of rotation of the handle. This two-armed lever 71 noscillates within the bridge 1'', Figs. 2 and 3, which is suitablyhollowed out, and the lever projects with the flat widened ends of itstwo arms into the tubes 7*, carrying the oculars.

Two apertures are formed in each of the flat or plate-like ends of thislever. In one of these apertures of each arm a convex glass 19 isinserted, while the second aperture (1 is free. The outward movement ofthe lever n n is limited by the ends of the plate-shaped extensionsencountering the wall of the tube r, and these plate-shaped extensionsare so designed that when the lever is at one limit of its position thecenters of the two convex glasses 1? coincide with the center lines ofthe objectives and the oculars, Figs. 1 and 2, while in the second limitposition of the lever these center lines pass through the center of theapertures q before mentioned, Figs. 2 and at.

Each objective 0 is mounted in a tube r which is screwed into the bridge'6 Fig. 5, and is adjustable on a tube 0" screwed to the bridge 2' Thebridge i carries a tube which adjusts itself on the tube 70, revolublymounted in the bridge The tube 7c is closed below. A spiral spring .5 isarranged in the tubes 7a and 7c, the upper counter-stop of such springbeing formed of a ring 6, sol dered or riveted firmly in the tube 70.

The spring 3 has a constant tendency to push forward the tube 70' andwith it the IOC bridge 2' of the tube 1' and the objective 0. Thismovement is limited by the outwardlybent front edge 3 of the tube r andby an inwardly-projecting projection 31' on the tube T The securing ofthe tube 9' when the glass is shut up takes place by means of the pin h,one end of which projects from the tube 70, which pin on the pushing inof the tube r first enters into a groove to, Fig. 3, provided in thebridge Z, and on the turning of the smaller lever or knob Z, andtherewith also of the tube 71;, is transferred into a horizontal branchof this groove u. V

A fiat spring 0 is mounted on the bridge 2' in the slot in which theknob Z may be moved to and fro, which spring prevents any turning backof the small lever or knob when it is in the position shown in Fig. 3.The objectives 0 are then pushed out. If they are to be again pushed in,a pin 10, attached to the bridge i, Fig. 3, pushes the spring 1) back insuch a way that the knob Z can be turned back again as far as up to thepin 10.

The mode of using the field-glass hereinbefore described is as follows:Assuming that the objectives 0 are in a pushed-in condition and aresecured in this position by means of the pin 71, engaging in the grooveu, by moving into a suitable position the knob Z the convex glasses 1)are thrown into position. The fieldglass is therefore in the conditionshown in Fig. 1. In consequence of the refraction again produced by theconvex glasses 1) the focal distance of the objective, which of itselfextends up to the point 1, Fig. l, is limited or shortened to the point2, and thereby the field of vision increased, but simultaneously alsothe absolute magnifying power diminished of itself. The oculars a, areadjusted to the eye by means of the set-screw b. If,

then, any object in the field of vision is to be subjected to a morecareful inspection, it is brought as far as possible into the center ofthe field of vision, and then by pressing the finger on the knob Z,without removing the field-glass from the eye, the knob Z is turned intothe position shown in Fig. 3, when the lever n n makes, in the mannerhereinbefore described, such a movement that the free apertures q takethe position of the convex glasses p, and simultaneously the fastening hu is released, that is to say, the compressed spring 5 is released, andthus the objective 0 is thrown forward. The extent .2 of this forwardthrow, Fig. 3, is equal to the distance apart of the two focal distances1 and 2, so that the field-glass then'acting with full magnifying effectremains in focus with the eye and allows the object in question to beimmediately inspected more distinctly.

Having now particularly described and ascertain ed the nature of thesaid inventionand in what manner the same is to be performed, I declarethat what I claim is-- 1. In a field-glass with adjustable magnifyingpower, the combination with oculars a, of

convex glasses p placed in front of them and of a small lever or knob Z,which simultaneously moves aside the said convex glasses p and causesthe objectives 0 to be pushed out to an extent .2 which equals thedifference of the focal distances of the objective alone and of itscombination with the convex glass 1) inserted in front of the ocular,substantially as described.

2. In a field-glass of the kind described, the combination withobjectives 0 and means for securing the small lever or knob Z, of aspring 5 which pushes forward the objectives, and of a pin w fixed inthe bridge 1 carrying the objective tube r whereby the knob Z is againreleased, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

EMILE TOUSSAINT.

Vitnesses:

ERNST DILLAN, EMIL T. HOFFMANN.

